1. Field of the Invention
The invention is directed to a process for the disposal of filter dust, sludge and ash in which the material to be disposed of is combined with the meltable slag of an electric low-shaft furnace. The invention also relates to low-shaft furnaces which are suitable for implementing the process.
2. Description of the Prior Art
A process for the disposal of bulk materials is known from the German Patent 38 30 392. In this process, filter dust or sludge is introduced into a slag layer located in an electric furnace. Injectors, immersion lances, screw conveyors or agitators are suggested as devices for charging the materials to be disposed of. By introducing the bulk materials directly into the slag, the disposal capacity is limited by the short dwell time in the slag, among other things.
A method for disposal of filter dust in which the dust is blown into a vessel containing the process slag outside the plant is known from the German Patent 39 30 852. In this case, the immersion depths and angular position of the lance are adapted to the dust charge. The subject matter of this patent concerns influencing the foaming of the slag when the dust is blown in. This patent does not mention the adjustment of the immersion depth as a function of the lance consumption.
Further, the German Patent 29 00 864 describes a method for blowing powdered material into a metallurgic melt in which the powder is conveyed below the surface of the melt by carrier gas under particularly high pressure. In this process for oxidizing and/or refining metallurgic melts, only small quantities of powdered material can be introduced into the melt. The processes mentioned above substantially influence possible recycling, particularly deposition of the slag.